NAME

       xss-lock - use external locker as X screen saver

SYNOPSIS

       xss-lock [-n notify_cmd] [--ignore-sleep] [-l] [-v|-q] [--] locker [arg] ...
       xss-lock --help|--version

DESCRIPTION

       xss-lock hooks up your favorite locker to the MIT screen saver extension for X and also to
       systemd's login manager. The locker is executed in  response  to  events  from  these  two
       sources:

       • X  signals  when  screen saver activation is forced or after a period of user inactivity
         (as set with xset s TIMEOUT). In the latter case, the notifier command, if specified, is
         executed first.

       • The  login  manager can also request that the session be locked; as a result of loginctl
         lock-sessions, for example. Additionally, xss-lock uses the inhibition logic to lock the
         screen before the system goes to sleep.

       xss-lock  waits  for  the  locker to exit -- or kills it when screen saver deactivation or
       session unlocking is forced -- so the command should not fork.

       Also, xss-lock manages the idle hint on the login session. The idle state of  the  session
       is directly linked to user activity as reported by X (except when the notifier runs before
       locking the screen). When all sessions are idle, the login manager can take  action  (such
       as suspending the system) after a preconfigured delay.

OPTIONS

       -n cmd, --notifier=cmd
              Run  cmd  when  the  screen saver activates because of user inactivity. Shell-style
              quoting is supported. The notifier is killed when X signals user activity  or  when
              the locker is started. The locker is started after the first screen saver cycle, as
              set with xset s TIMEOUT CYCLE.

              This can be used to run a countdown or (on laptops) dim the screen before  locking.
              For an example, see the script /usr/share/doc/xss-lock/dim-screen.sh.

       -l, --tranfer-sleep-lock
              Allow  the  locker process to inherit the file descriptor that represents the delay
              lock obtained from  the  login  manager.  The  corresponding  index  will  be  made
              available  in the environment variable $XSS_SLEEP_LOCK_FD; this will only be set if
              the reason for locking is that the system is preparing to go to sleep.  The  locker
              should close this file descriptor to indicate it is ready.

              Example    scripts    that    wrap    existing    lockers    are    available    as
              /usr/share/doc/xss-lock/transfer-sleep-lock-*.sh.

       --ignore-sleep
              Do not lock on suspend/hibernate.

       -q, --quiet
              Output only fatal errors.

       -v, --verbose
              Output more messages.

       -h, --help
              Print help message and exit.

       --version
              Print version number and exit.

SIGNALS

       SIGHUP Upon receiving this signal, xss-lock resets the  screen  saver,  but  only  if  the
              screen is not currently locked (unlike xset s reset).

              This  can  be used in MPlayer's configuration as a workaround for MPlayer's failure
              to restart the screen saver timer when playback is paused:

                 heartbeat-cmd="killall -HUP xss-lock"
                 stop-xscreensaver=false

              NOTE:
                 This is ineffective with mplayer2 (and mpv), because  its  heart  keeps  beating
                 while playback is paused.

       SIGINT/SIGTERM
              Upon  receiving  this  signal, xss-lock exits after killing any running notifier or
              locker.

NOTES

       • Some applications rely on the xdg-screensaver script from xdg-utils, which uses  xset  s
         off  and xset s default to suspend and resume the screen saver, respectively. The latter
         resets the timeout and cycle to the server defaults (xset s on uses a hardcoded  default
         instead), so this only works if you are happy with (or can control) the server settings.

         To  fix  the  resume action in this script (or a copy in ~/bin preceding the original in
         $PATH), either replace on by your preferred timeout and cycle, or avoid  hardcoded  time
         values  by patching the script to run a suspend loop as it does for other screen savers,
         using /usr/share/doc/xss-lock/xdg-screensaver.patch.

EXAMPLES

       • Run xlock after ten minutes of inactivity:

            xset 600
            xss-lock xlock +resetsaver

         Without +resetsaver, xlock forces a screen saver reset during startup,  thereby  telling
         xss-lock to immediately kill xlock again.

       • Dim  the  screen  after  three  minutes of inactivity, lock the screen two minutes later
         using i3lock:

            xset 180 120
            xss-lock -n dim-screen.sh -- i3lock -n

         NOTE:
            A script is provided to use  i3lock's  forking  mode  with  the  --tranfer-sleep-lock
            option (see above).

SEE ALSO

       xset(1), systemd-logind.service(8)

AUTHOR

       Raymond Wagenmaker <raymondwagenmaker@gmail.com>

                                          November 2013                               XSS-LOCK(1)